548 



SCIENCE. 



|Vol. VII, No. 176 



the reverse is inscribed " M. Spencer F. Baird, 

 United States commissioner of fish and fisheries," 

 and the legend "Department de la Seine-In- 

 ferieure. La commission de pisciculture. 30 

 Novembre, 1885.'' The medal is about the size of 

 a double eagle. It will be placed on exhibition 

 in the north hall of the national museum. 



— M. Charpentier, in a late session of the 

 French academy, called attention to the follow- 

 ing visual illusion : after a small, feebly illumi- 

 nated object has been attentively viewed for some 

 time in complete darkness, it will often appear 

 to move in some determined direction in the field 

 of vision, at a speed varying from two to three 

 degrees per second, and sometimes through a dis- 

 tance subtended by an angle of thirty degrees or 

 more. M. Charpentier states that this illusion 

 occurs in the fixed eye observing a fixed point, 

 but it is doubtful whether he is correct. Muscae 

 volitantes, or floating spots due to impoverished 

 blood or disease, have a like tendency in the closed 

 eye, when attention is directed to them, of moving 

 off in some determined direction, apparently as if 

 floating upon the vision ; but a finger placed upon 

 the eyeball will at once detect that the spots are 

 fixed upon the retina, while it is the eye itself 

 that moves. 



— A recent examination of the employees of 

 certain French railroads for color-blindness, made 

 in compliance with the instructions of the minis- 

 ter of public works, resulted in the detection of 

 only two persons who were totally color-blind 

 among 11,173. Three could not distinguish red, 

 six green ; eighteen showed a confusion in distin- 

 guishing between green and red, fifteen a like 

 confusion between blue and gray ; and fifty-two 

 had a feeble sense of colors in general. These 

 results show that the danger arising from color- 

 blindness, on the French railroads at least, is al- 

 most nil. As is seen, not more than two per cent 

 of the employees had imperfect sight, so far as 

 colors in general were concerned, and not more 

 than a half of one per cent were troubled with 

 color-blindness in any way. 



— During the year 1885 there were 155,177 

 German emigrants from the ports of Hamburg, 

 Bremen, and Stettin, a decrease of over 40,000 

 from the preceding year. Of this number, 148,- 

 839 were immigrants to the United State3. 



— The coast-survey changes since our last issue 

 are as follows : the party in charge of Assistant 

 F. W. Perkins lias returned from the south coast 

 of Louisiana. The latter has gone t<> his home to 

 work up the results of the trip; Captain Vina] 

 has finished the gap on the west coast of Florida 



in Hernando county (this completes the ocean 

 shore-line of that coast, except a small strip near 

 the Thousand Islands) ; Assistant Pratt, who is on 

 the north-west Pacific coast, reports the govern- 

 ment telegraph-line from Tatoosh Island to Port 

 Angeles, Washington Territory, as so badly ground- 

 ed that it is impossible to exchange time-signals 

 for longitude over it. 



— The Zuni maiden Wa-Wah, who has been in 

 Washington as the guest of Mrs. James Stephenson 

 for several months, is now engaged in weaving a 

 blanket in the national museum, on the loom pro- 

 cured by that institution from the Zuni Indians. 

 The loom, with the blanket upon it, will be placed 

 in a case in the museum, together with photo- 

 graphs of Wa-Wah at work upon it. which will 

 illustrate the mode of weaving employed by the 

 Zunis. Wa-Wah is well versed in all the mys- 

 teries of the Zuni religion and the customs of her 

 people, and has given Mrs. Stephenson and the 

 museum authorities much valuable information. 

 She took great interest in the model of the town 

 of Zuni at the museum, and gave testimony of its 

 accuracy by pointing out her own house. She will 

 go back to her home in the Zuni country with the 

 geological-survey party, who will visit that region 

 next month. 



— M. Tourette has recently published certain 

 results of observations on the gait in walk- 

 ing, in health and in various pathological states, 

 which are of interest. The average full or double 

 normal step he finds in the adult man to be sixty- 

 three centimetres ; in woman, fifty centimetres ; 

 in both sexes the right step is a little longer than 

 the left. The average separation of the feet, or 

 the base of support, in man in walking, is from 

 eleven to twelve centimetres ; in woman, twelve 

 to thirteen ; in both sexes the lateral distance, 

 being one centimetre greater on the left side. 

 The sum of the divergence between the axes of 

 the feet and the axis of direction is, in man, 

 thirty-one or thirty-two degrees, the angle being 

 about one degree greater on the right side; in 

 woman, thirty or thirty-one degrees, with one 

 or two degrees greater divergence. In one of 

 the pathological types occurring in locomotor 

 ataxia, in paralysis agitans, etc., the step is 

 smaller, and the distance between the feet as well 

 as the angle between them is larger, than normal 

 Another type, seen in diseases of the spinal cord, 

 hemorrhages of the cerebellum, and in vertigo, 

 shows a zigzag manner of walking. The step 

 may be either short or long: in either case the 

 footprints are confused and indistinct, and deviate 

 from the line of walking. Other differences have 

 been wrought out. Perhaps the most unexpected 



